Process of catalytic hydrogenation



Oct. 26, 1943. H. .1'. Hr-:P ETAL 2,332,572

I PRocEss oF GATALYTIG HYDIRoG-ENAT'loN Filed April 2.' i940 2 sheets-sheet 2 HAROLD J. HFJPPA JEAN P. JONES v ATTORNEY f Patented Oct. 26, 1943 v UNITED STATES PATENT OFFICE PROCESS F CATALYTIC HYDROGENIATION i Harold J. Hepp and Jean P. Jones. Bartlesville.

Okla., assignors to Phillips Petroleum a. corporation of Delaware 1 Company,

Application April 2, 1940, Serial No.- 327,518

1l Claims.

amount of heat liberated is of the order of 30,000

calories per gram-mole. This is enough heat to raise the temperature of a stream of vaporous diisobutylene, for example, from 400 F. to 1010 F. When the hydrogenation is eii'ected with the aid of a catalyst, control of the temperature of the catalyst is highly important. If the temperature is not controlledl properly, portions of the catalyst become overheated or underheated; this results in undesired products from side re-- actions such as destructive hydrogenation, in a decreased yield, and often in an increased rate of deactivation and/or deterioration of the catalyst. overheating of the catalyst is especially detrimental, as itmay destroy part or all of the catalytic activity.

overheating of the catalyst, for example, may occur because of the development of localized hot spot or zone in which an overly large fraction of the hydrogenation takes place. The pro. duction of such a hot zone isfavored when the concentration of the reacting ingredients is high, at moderate to high superatmospheric pressure,

for the reaction occurs at a rate that is determined largely by the concentration of the reactants. The-heat liberated by the hydrogenation causessuch a cumulative increase in the temperature that the catalyst becomes overheated. As anoverly large fraction of the hydrogenation takes place in the hotzone, other parts of the catalystvdo not effect their proper share of the hydrogenation; In other words, the part of the catalyst within the hot zone carries more than Y its share of the load andthe parts outside of the hot zone carry less than their share.

This condition is. especially undesirable because the hot zone doesnot remain in one place; in consequence of the destruction'of the catalyst. it.

moves in the direction of the ow of the reactants. The result is that the destruction of the catalyst is not limited to a small zone or amount but progresses throughout theaentire body of catalyst, and eventually` aects it all. Serious losses of catalyst, reductions Vin yields, production of impurities and other disadvantages result from such uncontrolled mode propel-ation.

(Cl. 26o-676) Inthe past, control of the temperature in exoi thermic catalytic conversion processes has been .effected usually by means of a uid medium'in heat-exchange relationship with the catalyst.v ToA 5 be successful, this scheme requires that the heat exchange be highly eiiiclent. The reaction therefore is effected generally in a multiplicity of relatively small and/or narrow catalyst chambers arranged in heat-exchange relationship with the temperature-controlling medium.- Such ,catalystchambers are made usually of tubes having a diameter of the order of 0.5 to 1.5 inches, or o! concentric tubes that' form annular zones llaving a thickness of the same order oi magnitude. 'n Heat is removed by the temperature-controlling medium, which/is in contact with the walls or the catalyst chambers. Equivalent systems in which temperature-controlling means are placed in'contact with the catalyst, such as tubular members positioned within the catalyst body and containing a liquid vo1' lsuitable boiling point or some other temperature-controlling iluid me dium, have also beenproposed.V

Such previously proposed catalytic conversion systems have a number of outstanding disadvantages, among which may be mentioned: the high cost of manufacture oi .the many catalyst chambers required; A the high cost of certain heatexchange media such as mercury, diphenyl. and thelike; the diiiiculty'of making and maintaining fluid-tight connections or joints; the com V parative inconvenience of -;replaoement ot catalyst; and the diiliculty of preventing leakage 'of thel temperaturewontrolling' medium, which may be toxic as well vas expensive. In spite. of these disadvantages, such systems have been used because many catalytic conversions must be effected within narrow temperature limits. II an eilicient heat-exchange relationship is not maln- 40 tained, the catalyst may become too hot; this may result inthe production of impurities in the i product lby destructive` hydrogenation and/or other undesired reactions and may have a deleterious effect upon the activity of the catalyst'.

The necessityoi an eiilcient heat-exchange relationship between the Acatalyst and the temperavture-controlling medium precludes the use of a comparatively large body of catalyst in an individual catalyst chamber; s

improved process for eiecting the catalytic,` nonf destructive, liquid-phase hydrogenation. of

organic compounds. c p

Another object of this invention -is to eilect .55 a controlled uquis-pnasanon-destruaiye hydr.

It is an objects: this invention to provide an` the following description, the accompanying v drawings, and the appended claims.

We have found that liquid-phase hydrogenation of organic compounds, such as unsaturated hydrocarbons in the gasoline boiling range, may be eiiected in an efcacious, economical, and advantageous manner by carrying out the hydrogenation in the presence of an inert diluent having a boiling point appreciably lower than that of the compound being hydrogenated. Diluents suitable for use in our process are any materials that are inert under the conditions prevailing in the catalytic hydrogenation chamber, and that have boiling points or ranges appreciably lower than that of the material being hydrogenated by a difference of from about 50 to 300 F., preferably a difference between about '75 and 150 F. In any case such a low-boilingdiluent must be miscible in all proportions with thematerial to be hydrogenated at the temperatures of hydrogenation, and it must be capable of existing in appreciable proportion in the vaporphase at or just above the lowest temperature at which hydrogenation is to be effected. A low-boiling diluent with a narrow boiling range is often most desirable and for this reason the use of essentially pure compounds is generally preferable. However, mixtures of two or more compounds having boiling points close together, the mixture having a narrow boiling range, such as a range of not more than about 75 F., are often more readily available, and are quite readily used provided that the highest temperature of the boiling range is at least about 50 F. below the lowest boiling point of the material being hydrogenated, all such boiling points being measured at atmospheric pressure. In many cases a mixture having such an appreciably extended boiling range is more desirable as a low-boiling diluent than a pure compound, as this will tend to insure the presence of material being vaporized, and absorbing heat of reaction, throughout a greater length of the catalyst chamber. The use of a low-boiling diluent with such a boiling range is one of the features of our invention.

The hydrogenation is carried out in an essentially vertical catalyst chamber containing a body, or bodies, of solid hydrogenation catalyst and with the material undergoing hydrogenation and the saturated products produced being substantially in the liquid-phase, throughout the course of the hydrogenation. A liquid comprising Without appreciable channeling. Saturated organic material, substantially in the liquid phase. I

any known hydrogenation catalyst that is suitable for the non-destructive hydrogenation of the unsaturated organic material charged to the process. It is important, however, when a bed of catalyst is used, that the body of catalyst be comprised of large particles, .with -few if any small particles being incorporated therewith. It may, at times, be possible or desirable to have the catalyst in one large body resting upon a support, such as a perforated false bottom, placed near the bottom of the catalyst space, especially if this body of catalyst is made up of large pieces of solid material. However, it will generally be more desirable to have the catalyst body consist of a number of smaller bodies resting on supports so that, between each of the smaller bodies of catalyst there is ample space for a separation between liquid material flowing downwardly and material flowing upwardly in` the vapor state. At times it may be desirable and expedient to form the catalyst particles in special shapes, such as a shape similar to a Raschig ring or the like, or the shape of other materials used in the packing of fractionating and/or absorption equipment and known to those skilled in the art. Such special treatment will,

at times, give better contact between gaseous hydrogen and unsaturated liquid as well as aiding in the counter-current flow of gases and liquids.-

If it should be possible or desirable to incorporate a mobile catalyst in the liquid comprising unsaturated organic material and diluent, such as a liquid catalyst, or one soluble in or suspended in the liquid, ordinary bubble-trays or other conventional packing made of inert material vmay be used, with thecatalyst-containing liquid flowing downwardly in a manner similar to that of an absorption oil, and being discharged from the chamber at the bottom, with hydrogen-containing vapors owing in counter-current, direct contact. In any' case, by catalytic hydrogenation chamber will be understood that portion of the chamber `wherein a catalytic hydrogenation takes place.

The temperature at the top of the catalyst bed should be a reaction temperature, so that some reaction will take place between unsaturated material and hydrogen. The temperature will tend to be higher in lower parts of the catalyst chamber, with the highest temperature at or quite close to the bottom of the chamber. However, due to the evaporation of the low-boiling the unsaturated organic material and an inert r diluent having a substantially lower boiling range, is introduced to the top portion of the catalyst bed, and hydrogen. preferably in excess inert diluent, the diierence in temperature will not be extreme. When our process is operated for the catalytic hydrogenation of olens in the motor fuel boiling range, temperatures at the top willgenerally not be less than about 75 to F. and should not be greater than about 00 F., and will preferably be between 250 and The amount Vof low-boiling diluent will be somewhat dependent upon the charge stock, especially the concentration of unsaturated material in the total liquid introduced to the top of the hydrogenation'chamber: upon the reaction temperature as-it relates to the boiling ranges of the material 'being hydrogenated, the low-boiling ranges of this diluent and the heavier material; and upon the relative hydrogen partial pressure. The total liquid material charged to the top portion of the hydrogenation chamber should not contain more than about 50 mol per cent of unsaturated material, and preferably between the concentration-of unsaturated material be low if this material is highly unsaturated, as when an aromatic compound such as benzene or toluene is to be hydrogenated to a naphthene such as cyclohexane or methyl cyclohexane, etc. Some of the remainder of this liquid material may be saturated material which has essentially the same boiling range as the unsaturated material to be hydrogenated, such as will be present when a part of the saturated product is recycled. This saturated material will, in eiiect, be an inert diluent, but it is to be distinguished 'from the lowboiling, inert diluent charged to the process in accordance with our present disclosure.

The highest temperature of hydrogenation must, of course, be appreciably below the critical temperature of the material being hydrogenated,

- and the reaction temperature near the top of the hydrogenation chamber must'be well below the critical temperature of the total mixture charged to the process at this point. However, it is not essentially necessary' that the critical temperature of the low-boiling diluent be above the reaction temperature at the top of the hy-v drogenation chamber, as this diluent can be in solution in the liquid material to be hydrogenated under such conditions, and even somewhat above its own critical temperature this diluent will have 'a substantial heat of vaporization when it va- A its vaporlpressure in this region will be quite high, and relatively more of the rdiluent must be used in order to insure that a sufcient quantity is present in solution. higher hydrogenating temperatures by employing a diluent which has as high a boiling point, or range; as possible while still having it suillcientlybelow the boiling range of the heavier material 'asto be vaporized during hydrogenation without undue vaporization of the material being hydrogenated. As the hydrogenation catalyst becomes deactivated. it will generally benecessary tol raise the hydrogenation temperature inorder to maintain the same amount of hydrogenation.

If the process is conducted initially using a low-g boiling diluent which has a normal boiling point rather widely separated from the heavier, unsaturated material, it may` bedesirable, and is apart of our invention, to add a low-boiling diluent` whose normal boiling temperature is -not so widely separated from the unsaturated` material as it becomes necessary to raise the .hydrogenation temperature.A A

With the limits just discussed in mind, the inert, low-boiling diluent should comprise at least about 20 mol per cent of the total liquid mixture enteringthe top of the hydrogenation chamber,

. and may be as highas about 80 mol per cent of This is best done at the about 20 and 40 mol per cent. Especially should this liquid. Based on the amount of unsaturated material present, the diluent should be between 1 and 6 times the molar quantity of unsaturated material, preferably about 2 to 4 times this quantity. When hydrogenating `a rather pure material such as a mixture of isooctenes, a low-boiling diluent such as butane or pentane, or mixtures thereof, may be used, and although some propane might be used in a mixed diluent, pure propane is too volatile for satisfactory use, although, propane could be used with pntenes and hexenes.

With a mixture, such as. a mixture predominating in heptenes, octenes and nonenes, butane is better as a diluent than pentane, although a mixture of' butanes and pentane, especially isopentane, canv be used. When the material to be hydrogenated consists of a heavy naphtha, such as one with an initial boiling point of about 300 F., the low-boiling diluent may conveniently `be a heptane or volatile octane at a hightempera ture of hydrogenation. while butane or pentane may be used at lower hydrogenation temperatures and will be somewhat more desirable. For any particular unsaturated material and hydrogenation temperature range, the low-boiling diluent to be used,r and the amount of such diluent may be readily determined by trial by one skilledintheart. Some control of the ease with which the lowboihng diluent .may vaporize when in the hydrogenation chamber may at times be eiected by I controlling the pressure within lthe chamber.`

However, in general .we contemplate the use of a substantially constant pressure throughout the course' of a given cycle of operation, which will be -limited by amount of charge stock, catalyst activity or the like. The process is to be operated under an appreciable super-atmospheric pressure of at least pounds per square inch, and may be at times as high as v2000 or 3000 -poundsper square inch or more, with a preferable range between about 200 and 1500 pounds per square inch.

The invention will nowbe described with ref, erence to the accompanying drawings, inl which Figure 1 shows a diagrammatical view of apreferred arrangement of apparatus for practicing our invention and Figu're 2 showsa modiiled arrangement of apparatus. It will be obvious to those skilled in the art that modifications other than the specific arrangements shown may be used without passing ybeyond the scope of the invention.

- The liquid feed-stock, containingun-saturated.

organic compounds,'such an oleiin hydrocarbons boilingin the motor-fuel range, is charged to the Aprocess through pipe I0, which leads to a manifold II from which lead pipes such as I2,

I3 and I4 having control-valves I5, I8 and I1,

respectively. In inert, low-boiling liquid' diluent, having a boiling point appreciably lower than the average boiling point'of the feed stock, such as butane, is charged to the process -through pipe I8, inan amount controlled by the .valve I9, and passes to manifold 20. This diluent, augmented by recycled low-boiling diluent from pipe 31, is

distributed in any desired manner through the branch-'pipes 2|, 22 and 23, which are provided with control-valves 2l, 25 and 2B,' re`spectlvely,

into the branch-pipesv I2, Iland Iljaforemen-A tioned. The branch-pipes I2, Il and I4 convey the feed-stock and/or diluent to distributors 2l,

,28 and 29 positioned at suitable pointsin a catalytic hydrogenation chamber lvl.V j

Simultaneously hydrogen is charged to the process through pipe 43.

catalytic hydrogenwn chamber 3l!l through pipe 3| having contr '-valve 32. In the cata.-- 4 lytic hydrogenation chamber 30 vthe liquid hydrocarbons and the gaseous hydrogen pass counter-currentlywhile in contact with a suitable hydrogenation catalyst, not shown. lThe unsaturated organic compounds in thefeed stock undergo hydrogenation, whereby hydrogen is added to unsaturated carbon-to-carbon bonds, and much heat is liberated. The temperature tends to increase as a` result of the heat of hyaway by the vaporized diluent, which passes from the catalytic hydrogenation chamber through pipe 33, provided with a suitable valve. into the condenser and/or separating or-frac tionating means 34, and the main portion of the material being hydrogenated, and of the saturated product, remains in the liquid phase.

In the separatingA means 34 the gaseous material passing from the top portion of catalytic hydrogenation chamber 30 through conduit 33 is suitably cooled, by means not completely shown, so that most or all of the hydrocarbons are liquefied and especially substantially all of the heavier hydrocarbons in the motor-fuel boiling range. This liquid material is separated and returned to the` process, passing through pipe 35 controlled by valve 36, to conduit 31, pump 38, and continues through conduit 31 to manifold 20.

Hydrogen-containing'gases pass from the means 34 through pipe 39 and may be returned directly to the processthrough pipe 39, provided with a. valve 40 and a pump 4I, and pipe l42, or they may be discharged partly 'or completely from the process through pipe 43 provided with valve 44. If desired, part or all of the diluent may be allowedV to pass uncondensed through the separating means 34 and part or all of such uncondensed diluent' may be vdischarged from the The hydrogenated'material leaves the catalytic hydrogenation 'chamber 30'through pipe 45, essentially in a liquid state. It may be discharged from the process through control-valves 46 and 53 or it may be passed partly or totally through pipe 41 and branch-pipe 48,*provided with control-valve 49, into the separator or fractionator 50, which is provided with suitable heating and cooling means, not shown. In the separator 50, any of the low-boiling diluent remaining in the eilluent liquid from catalytic hydrogenator 30 may be removed, as by fractional distillation. The liquid product thus freed from the lowboiling diluent is discharged through pipe I controlled by valve 52. 'The diluent thus recov- If desired, hydrogen may be added to the material ilowing in branch-pipes I3 and I4 through manifold 5I and branch-pipes 62 and 6,3, which are provided with control-valves 64 and 65, respectively. 'I'he composition of the material passing rthrough the distributors 21., 28 and 29 in the catalytic hydrogenator 30 may be varied in any manner desired by means of control valves I5-I 1, 24-25, and` 64 and 65. For example, in a possible mode of operation, valves I6, I1, 64 and 65 n.ay be closed and liquid diluent alone may be passed through distributors 28 and 29 in 4amounts controlled by valves and 26 while a mixture of feed stock and diluent is vpassed through distributor 21 in amounts controlled by valves I5 and 24. Control of the amounts and the composition of the material entering chamber through distributors 21 29 is made in accordance with the requirements for satisfactory controlled hydrogenation as indicated, for example, by the temperature indicated by the thermometers 1I, 12 and 13, or as otherwise indicated by trial.

As a modification of our process, a portion of the hydrogenated product may be used as an absorption medium t0 aid in the separation of low-boiling diluent from the mixture of diluent` vapors and hydrogen passing from the top of the hydrogenation chamber 30. In such a modification, a portion of the hydrogenated product passing through conduit 45, either with or without stabilization in the separator 50, is passed through conduit and valve 61, aided by\proper control of valve 68 in conduit 45. The material passing through conduit 56 is passed through cooling coll 69 and conduit 10 to the top portion of separating means 34. The mixture of absorption medium and absorbed diluent, in the liquid phase,

passes from the separator 34 through conduit 35 and is returned to the system. If necessary, under someconditions a pumping means not shown may be inserted in conduit 66 and/or 10. If more of the hydrogenated product is used for such absorption of the low-boiling diluent than it is desired to return as high-boiling diluent to 'the process, means not shown may be inserted between separating means 34 and conduit 31 for effecting a separation of absorbed low-boiling diluent from the higher boiling, hydrogenated product.

For simplicity, the number of distributors shown in the drawings has been limited to three; any number, however, may be used in accordance with the requirements of any particular applicaerd may be returned to the process through pipe 53 controlled by valve 5.4, and through pipe 55 controlled by valve 56, passing on to pipe 31, or it may be discharged partly or totally from the process through pipe 51 provided with valve 58. If' desired, part of the ellluent liquid from catalytic hydrogenation chamber 3B may be recycled to the process directly by being passed from pipe 41 through pipe 53 controlled by valve 50 into Pipe 53.

'tion of our invention. Additional branch-pipes,

control-valves, and the like may be incorporated without passing beyond the scope of our invention.

The distributors 21 to 29 are adapted by any known means to provide even distribution of the material flowing through them into the catalytic hydrogenation chamber 30. Each may be constructed in the shape of a rose, as a perforated tube in the form of aloop or circle, or the like. If desired, the zones of the catalytic hydrogenator 30 in which the distributors are positioned may be kept devoid of catalyst, as for example by, the use of perforated partitions each supporting a limited portion of the total body of catalyst.

It may at times be more desirable to incorporate all or a part of the separating means 34 as a more integral part oi the chamber 30. In such a modification, the chamber will extend well above the top of the catalyst bed, and this valve |08 leads from manifold 20, and supplies a stieam of low-belang duuent'nuid to .the top bubble-tray. Il desired, Vthis stream may be cooled by passing all or a part of it through cooling coil |04, with valves and |06 being open and valve |03 completely Ior partially closed. This absorbent liquid ilows counter-current to land in intimate'cont'act with, -vapors and gases rising from the top of the catalyst bed and acts to remove and entrain with it any heavier mate-` rial introduced originally through conduit lli.` as

well as some of the lighter vapors.' With such a.

. assura trays or the like, as used in ordinary distillation 'After the process is in operation, only enough diluentneed b e added through pipe I8 and valve Il to compensate for that'carried vaway from the system with the nquxa prodlct through pipe 4s and/or that discharged from the system through pipe 43 and/or pipe 51.

We have found our poi-cess to be particularly( advantageous for the hydrogenation .of unsaturated hydrocarbons boiling in the gasoline range. As examples of such unsaturated hydrocarbons may be mentioned benzene and toluene and the like, and olefin hydrocarbons such as isomeric pentenes, hexenes, heptenes, octenes, nonenes, decenes, and the like, formed by the catalytic poly- ,-merization of olefins having lower mblecular weights. For the hydrogenation of such olen hydrocarbons a suitable diluent is a relatively low-boiling paraln hydrocarbon, such at butane I or pentane. If a higher boiling unsaturated hydromodiilcation, the hydrocarbon niaterial passed through conduit |02 to top bubble tray may adsaturated material being recycled through the hydrogenation process. This is accomplished vantageously contain large'amounts of heavier by passing such a stream from conduit 66 through conduit H5 controlled by a valve IIS, pump or compressor H9, and conduit |20-andvalve- |2| to conduit |02, valve H1 in conduit 66 being partially or completely closed, and valve ||8 in conduit |02 being completely closed if it is desiredthat this stream should consist entirely of heavier material. The absorption'liquid may alsol consist completely of. or partially comprise,-

liquid unsaturated material charged to the process for hydrogenation. This may be accomplished by opening valve |08.in conduit |01 which leads from manifold |I to conduit |02, with valve IIB being closed and valve |2| being partially or completely closed.,V The bottom bubble-tray l 0| may have a down-spout leading directly to the catalyst chamber proper, or the liquid on it may be removed, as shown, through a conduit I0 provided with a valve and leading'into the pipe 21,--

where it'mingles vwith the material in this pipe and passes, with it, to the catalyst chamber.

4Vapors and gases passing from the top plate will pass through valve-'controlled pipe 33( to conbauxite, etc., and with or without one or more carbon fraction is to be hydrogenated,such as an isooctene or an isononene fraction, a higherboiling hydrocarbon such as hexane may be used as an inert diluent, always provided that a suillcient temperature interval exists between the boiling range 0fl the unsaturated material and of the inert diluent used. For the hydrogenation of'hexenes at high pressures, propan'e may be used; isobutane and/or normal butane may be usedA at somewhat lower pressures. .fChoice of a suitable diluent for any selected conditions of pressure,

temperature and material being hydrogenated may be made readily by trial.

By the practice of this invention unsaturated hydrocarbons boiling in the motor fuel range, such as can be prepared by catalytic and/or thermal polymerization or conversion of gaseous oleiins, may be hydrogenated catalytically and nondestructively to saturated hydrocarbons suitable for use as motor or motor-fuel blending/stock. The hydrogenationis eiected in an easy, Aeconomical, and advantageous manner; the temperature of large bodies of catalyst is controlled and deleterious elects of excessive temperature avoided by the controlled addition of a diluent having a boihng point suitably lower thanthat of the material undergoing hydrogenation.

As an example of the operation of one modl'- cation of our process, an unsaturated hydrocarbon material comprising a mixture of isoheptenes and isooctenes produced by the catalytic copolymerization of the olens produced from the thermal dehydrogenation of a butane mixture, containing a large proportion of isobutane, was hydrogenated in the liquid phase'in the presence of a nickel-containing cataLvst comprising nickel,

copper, and alumina intimately associated upon a promotion materials. 'I he catalyst may be present as a single undivided batch, or body of catalyst particles, or it may be separated into portions of more or less equal size as by perforated partitions, trays, baskets or the like. We have found that a nickel-containing catalyst is especially eillcient in the saturation ofolen hydroporous support. The catalyst `is prepared by soaking at ordinary temperatures a body of pumice granules, comprising particles between 2 and 4 mesh in size, for abouta half-hour in a sub-- stantially saturated aqueous solution containing about equal amounts of nickel nitrate and aluminum nitrate and about one-quarter of this amount of copper nitrate. After this soaking' treatment the body of pumice, the particles of which are impregnated with these various niheated to a high temperature decomposing the nitrates. 'I'he resulting material is placed'in a hydrogenation chamber, a hydrogen-containing iiuid passed through the chamber, and the material is used as hydrogenating catalyst.

The hydrocarbon mixture just mentioned is inseveral streams are suitably controlled so that the temperature of the mixed streampassing A through distributor 21 has a temperature of 220? In this particular example, a total pressure of 750 pounds per square inch exists in catalyst chamber 30. Hydrogen is introduced into cat'al'yst chamber. by means of pipes 42 and 3| at a rate of 1450 cubic feet per hour, this rate Abeing controlled by means of valve I2.

Hydrogenation of the oleilns then occurs in the catalytic mass below distributor 21 with evolution of heat.4 This heatwill cause partial vaporization of the butane, along with a small portion of the motor-fuel boiling range stock, and a temperature rise -wili occur in the catalyst mass immediately below distributor 2l of lill-80 F. Upon condensation of the vapors by the means provided the heat is extracted and the hydrocarbons returned to the catalyst chamber il.

While in this example all of the hydrocarbon material is introduced through distributor 21. all or part of it may be introduced through the other distributors shown and this method of operation is preferred when the zone of maximum temperature moves down the column with the eventual decreased activity of the topmost portion of catalyst. Similarly. the temperature of the stream entering the distributors maybe adjusted to provide conditions required for maximum catalyst activity and life.

We do not wish to exclude from our invention n certain modications orvariations that will be obvious to those skilled in the art. For example,

various eiliuent streams may be placed .in heatexchange relationship with one or more ingoing streams to any desired degree or extent. Sumcient pumps have beenshown to permit and facilitate the operation of the process imder ordinary operation, but with certain particular -will likewise be obvious. and their inclusion or tenersi arrangement will not alter the flmdamentals of our invention. Hence, it is to be understood that..within the scope of the appended bottom and such that said unsaturated-material is substantially completely hydrogenated inliquid phase and such that only a portion of said more volatile inert liquid vaporises at tilel inlet to said zone and decreases in concentration in the liquid phase from the inlet to the outlet of said zone,

. passing to at least one intermediate point of said zone a liquid material comprising a further portion of said more volatileinert liquid to dilute said unsaturated organic material being hydrogenated and to inhibit a temperature rise caused by heat of reaction, passing'gases and vapors from the top portion of said zone', and removing al substantially saturated liquid material so produced from the bottom portion of said zone.

2. An improved process for. the vnondestructive hydrogenation of unsaturatedorganic compounds in thelliquid phase, which comprises passing a liquid mixture comprising an unsaturated organic material together with Aa more. volatile miscible inert hydrocarbon liquid to the top portion of a substantially vertical catalytic hydrogenation zone `containing va hydrogenation catalyst and wherein a downilowing liquid can pass coimtercurrentiy to an upfiowing gas, passinga gas containing free hydrogen to the bottom portion of said hydrogenation zone, removing hydrogenated material from the bottomportion of said zone, maintaining in saidzone reaction conditions such that the temperature is progressively higher from top to bottomv and such that said unsaturated material is substantially completely hydrogenated in liquid phase and suchthat only a portion of said more volatile liquid vaporizes at the inlet to-said zone and also such'that said hydrogenated material eiliuent from said zone is in liquid phase and is' relatively free of said more volatile liquid, the concentration of said lowboiling diluent in the liquid decreasing from top to bottom. passing gases and vapors from the top of said zone, recovering'as a liquid so recovered to the top portion of said catalytic hydrogenation zone as at least abortion of said initial inert liquid diluent material.

the invention is as extensive in scope and f 'equivalents as the prior art allows.

We claim:

l. 'I'he process of lcatalytic nondestructive hy' can pass oountercurre'ntly to an upiiowinggas,

passing a gas -containing free hydrogen to the bottom portionof said reaction sone, maintaining insaid sone reaction conditions auch that the temperature ls progressively higher from top to 3. An improved process for the nondestructive hydrogenation of unsaturated organic compounds in the liquid phase, which comprises passing a' liquid mixture comprising an unsaturated organic material together with a more volatile miscible inert hydrocarbon liquid to the top portion of'a substantially vertical catalytic hydrogenation zone containing a hydrogenation catalyst and wherein a downfiowing liquid can pass countercurrently to an upiiowing gas, passing a gas containing free hydrogen to the bottom portion of said hydrogenation zone,'removing hydrogenated material from the bottom-portion .of'said sone. maintaining in said sone reaction conditions such that the temperature is DlOlrlvely higher from top to bottom and such that said `unsaturated material is substantially completely hydrogenated in liquid phase and such that only a portion of said' more volatile liquid vaporises at-the inlet to said sone and also such that saidihydrogenated material eiiiuent from said sone is in 'liquid phase and is relatively free or ssidmore volatile liquid, A

said inert diluent being added in an amoimt sumcient to absorb as latent heat of vaporiliatlon a major portion ofthe exothermic heat evolved during the hydrogenation reaction and decreasing in concentration in liquid phase from top to bottom,passinggasesandvapors fromthetopof saidiionetoanabsorptionaorie.lilssinsalwr-A diluent -material boiling at least about 50 iii. below the lowest boiling portion of said unsatu-v rated material, to the top portion of a substantially vertical catalytic hydrogenation zone containing a. hydrogenation catalyst and wherein a downflowing liquid can pass countercurrently to an upilowing gas, passing a gas containing free hydrogen to the bottom portion of said hydrogenation zone, maintaining in said zone nondestructive hydrogenation conditions such that the temperature is progressively higher from top to bottom and such that said unsaturated material is substantially completely hydrogenated in liquid phase with concomitant vaporization of said inert diluent material, increasing the average hydrogenation temperature as said hydrogenation catalyst decreases in activity to maintain a substantially constant amount of nondestructive hydrogenation, and employing at elevated hydrogenation temperatures a higher boiling inert diluent than isemployed at lower hydrogenation temperatures, each said inert Amaterial being added in'an amount such that its vaporization takes up substantially all the heat of reaction.

5. An improvedprocess for the saturation of unsaturated materialwith free hydrogen, which comprises passing a liquid mixture, comprising an unsaturated organic material to which has been added at least 1 and not more than 6 times as much oi a miscible inert diluent material boiling at least 50 and not more than 300l F. below thev lowest boiling portion of said unsaturated material, to the top portion of a reaction zone in which there is present a hydrogenation catalyst, passing a hydrogen-containing gas to the bottom portion of said reaction zone, maintaining in said reaction zone a nondestructive hydrogenation temperature progressively higher from top to bottom and a hydrogenation pressure, said pressure being suflicient to maintain said organic material predominantly in liquid phase in said zone and also to maintain a concentration oi' said inert diluent in the liquid mixture at the temperature existing at the top of said reaction zone substantially the same as that in the mixture as introduced to said zone, the concentration of said low-boiling diluent in the liquid phase decreasing from top to bottom, removing from the bottom portion of said zone a liquid mixture containing saturated organic material and removing from the top portion of said zone a gaseous mixture comprising vapors of said inert diluent.

6. An improved process for the saturation of unsaturated hydrocarbons in the motor-fuel boiling range with free hydrogen, which comprises passing a liquid mixture, comprising unsaturated hydrocarbons in the motor-fuel boiling range having at least iive carbon atoms per molecule in admixture with between l and 6 times as much butane, to the top portion of a vertical reaction zone in the presence of a hydrogenation catalyst, passing a free hydrogen-containing gas to the bottom portion of said reaction zone, maintaining in said reaction -zone a nondestructive hydrogenation temperature progressively higher from top to bottom and a hydrogenation pressure, said pressure being sumcient to maintain hydrocarbons of at least five carbon atoms per molecule in liquid phase in said zone and also to maintain a concentration of butane in the liquid mixture at the top of said catalyst substantially the same as that in the mixture introduced to said zone, the concentration of said butane in the liquid phase decreasing from top to bottom, removing from the bottom portion of 'said zone a liquid hydrocarbon mixture comprising hydrocarbons in the motor-fuel range substantially saturated and substantially free of butane, and removing from the top portion of said zone a gaseous mixture of butane vapors and free hydrogen. Y.

'7. A continuous process for the nondestructiv hydrogenation of normally liquid oleiin polymers boiling within the gasoline range to produce the corresponding parafiins, which comprises passing Va liquid hydrocarbon mixture comprising such olens together with between one and six -times as much butane to the top portion ofA a substantially vertical catalytic hydrogenation zone containing a hydrogenation catalyst and wherein a downiiowing liquid can pass countercurrently to upowing vapors, passing a gas containing free hydrogen to the bottom portion of said zone, maintaining in said zone 'nondestructive `essentially parailin hydrocarbons boiling in the gasoline range so produced.

8, An improved process for the nondestructive hydrogenation of unsaturated organic compounds in the liquid phase, which comprises passing a liquid mixture comprising an unsaturated organic material to be hydrogenated to the top portion of a substantially vertical reaction zone containing a solid hydrogenation catalyst,'said catalyst being so arranged as to permit downward flow of liquids and countercurrent upward flow of gases, admixing with said liquid mixture a second liquid mixture comprising saturated organic material produced by said hydrogenation and an inert diluent material boiling between about '15 and 150 F. below the lowest boiling portion of said unsaturated material, passing a free hydrogen-containing gas to the bottom portion of said zone, maintaining in said zone a nondestructive hydrogenation temperature progressively higher from top to bottom and a hy- `drogenation pressure suchthat only a portion of said inert diluent material vaporizesl at the inlet to saidzone and such that the hydrogenated eiliuent of said zone is in the liquid phase and is relatively free of said inert diluent, the concentration of said low-boiling diluent in the liquid phase .decreasing from top to bottom, passing gases and vapors fromthe top'of said zone to an absorption means, removing from the bottom of said zone liquid hydrogenated organic material and passing a portion of the hydrogenated eiiiuent to said absorption means as an absorption liquid, and passing the liquid eiliuent of said absorption means to the hydrogenation zone.

9. The process of claim 8, wherein at least a portion of the free hydrogen eilluent of said hydrogenation zone is freed of diluent vapors and returned as recycle hydrogen to the vhydrogenation zone.

10. A process for the catalytic hydrogenation of an, unsaturated hydrocarbon material boiling in the gasoline range, which comprises passing a stream of said -material while in the liquid phase through a hydrogenation zonecontaining a hydrogenation catalyst at a hydrogenation temperature progressively higher in the direction of- -ilow of said liquid and a hydrogenation pressure in countercurrent flow to a stream of hydrogen, incorporating in said stream of unsaturated material a substantially lower boiling hydrocarbon diluent, inert under4 the conditions prevailing in the zone, said catalyst being sumciently active that the hydrogenation temperature can be maintained low enough to permit maintenance of the unsaturated material in the zone substantially in the liquid phase, said 'diluent being suiciently volatile that substantial vaporization thereof takes place during the reaction under the conditions prevailing in the zone with a concomitant decrease in concentration of said diluent in the liquid phase in the direction of flow of said liquid, and said diluent being added in suiilcient quantity to absorb as latent heat of vaporization a major portion of-the exothermic heat evolved during the hydrogenation reaction.

1l. In a process forthe catalytic. nondestructive hydrogenation of unsaturated organic materials in which such organic material is passed through a hydrogenation zone in countercurrent flow to a stream of free hydrogen under a hydrogenation temperature in the presence of a hydrogenation catalyst and at a pressure suiiicient to maintain a major portion of such organic material in the liquid phase, themethod for controlling temperature rise due to the exothermic heat evolved as the hydrogenation reaction proceeds -during passage of such organic material through said zone which comprises diluting the organic material with a suilicient quantity of a substantially more volatile hydrocarbon diluent in the' liquid state, inert under the conditions prevailing in the chamber. to absorb a'major portion of the exothermic heat liberated by the reaction, the aforesaid pressure being so regulated that vaporization of inert'diluent. at the temperature prevailing at the point of introduction'to the chamber is not substantial but -becomes substantial as the material in liquid phase ilows through said zone and the reaction proceeds and the temperature rises, the concentration ot said diluent in the liquid phase decreasing in the direction of ilow of said liquid.

- HAROLD J. HEPP.

JEAN P. JONES.

l .CERTIFICATE 0F CORRECTION. l Patent No. 2, 552,572. october 26, 191g.

HAROLD J. HEPP, AL.

It is hereby certified Chat error appears in the printed specification of the above numbered patent requiring correction as follows: Page `5, sec- .ond colmnn, line 55,-fer.an" read asv; line 60, for "In" read --An-f-g and"that", the said Letters-Patent ehouldbe read with this crrection ltherein that the seme may confemto the'recordof the caseinthe Patent Gffice.

Signed and '.-s'ealed this 1+i-ix of Jeu'ary', A.. D; lllll' Henry van Andale, (Seal) Acting ommiasiener of Patents. 

